This application is related to and claims priority from Japanese Patent Application No. Hei. 11-276764 filed on Sep. 29, 1999, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention generally relates to a cooling device for cooling an inner part of an approximately sealed box by a heat-exchange between air inside the box and air outside the box. More particularly, the present invention relates to a waterproof structure of a heat-exchanging device.
2. Description of Related Art
In a conventional cooling device for cooling a heat-generating member such as an electromagnetic member used within a sealed cabinet, a heat exchanger is disposed in the cabinet so that an inner part of the cabinet is cooled by performing a heat-exchange between air inside the cabinet and air outside the cabinet. However, because it is necessary to have a waterproof structure when the cabinet is disposed at an exterior space, an outer peripheral part of the heat exchanger is potted by a potting resin material so that a waterproof line is formed around the heat exchanger in the cooling device. Therefore, a potting process of resin material is necessary, and assembling steps of the cooling device become trouble. Further, when once the waterproof process is performed, it is difficult to remove the heat exchanger from a casing of the cooling unit, and maintenance performance of the heat exchanger is deteriorated.
In view of the foregoing problems, it is an object of the present invention to provide a heat-exchanging device that cools or heats an inner part of an approximately sealed box by a heat-exchange between air inside the box and air outside the box, while improving operation performance, waterproof performance and maintenance performance thereof.
According to the present invention, in a heat-exchanging device attached to a box to form an approximately sealed inner space within the box, a heat exchanger has therein a plurality of inside air passages through which inside air inside the box flows, and a plurality of outside air passages through which outside air outside the box flows. The inside air passages and the outside air passages are alternately adjacently arranged in the heat exchanger, and the heat exchanger is accommodated in a casing having an outer wall surface in which an outside air introduction port for introducing outside air into the outside air passages and an outside air discharge port for discharging outside air from the outside air passages are provided. In the heat-exchanging device, the heat exchanger is disposed in the casing to form a space having a predetermined distance between the heat exchanger and the outer wall surface, and the outside air passages are provided to communicate with the outside air discharge port through the space. Thus, even when rain water is introduced into the casing from the outside air discharge port, the rain water flows downwardly in the space between the heat exchanger and the outer wall surface of the casing, and therefore, it can prevent the rain water from being introduced into the heat exchanger.
Preferably, the casing has a drain passage communicating with the space, and the drain passage is provided at a position lower than a bottom surface of the heat exchanger. Therefore, rain water introduced into the space from the outside air discharge port can be readily discharged to a lower side of the heat exchanger.
The heat-exchanging device further includes a seal member through which a boundary part between the inside air passages and the outside air passages of the heat exchanger is water-tightly detachably attached to an attachment wall surface of the casing. Therefore, the heat exchanger can be readily detached from the casing after being assembled to the casing, and maintenance performance of the heat exchanger is improved. Further, because the boundary part of the heat exchanger is water-tightly attached to the attachment wall surface, seal performance of the heat-exchanging device between inside air side and outside air side can be improved.
More preferably, the inside air passages and the outside air passages are provided in such a manner that both the outermost air passages of the heat exchanger are two of the inside air passages. Therefore, wall parts defining the outermost inside air passages can be used as seal surfaces to be attached to the attachment wall surface of the casing through the seal member. Thus, waterproof performance of the heat-exchanging device can be further improved.